Navigation devices, including portable navigation devices (PNDs), have become more popular and affordable recently for most users. The navigation device can, not only determine the driver's current position by utilizing the Global Positioning System (GPS), but also provide different routing information between the vehicle's current position and the destination. In order to perform abovementioned functions, the navigation device is usually equipped with a sophisticated navigation system comprising navigation computer programs and one or more detailed database to store and provide maps, road networks, geographical features, and waypoint or point-of-interest (POI) information.
More particularly, in a map database, major links such as freeways, highways and streets connecting to major arteries include lane count, lane connectivity, merge and lane expansion, and lane accessibility information. The navigation device is expanding its proximity radius based on the map-matched link as a center point, to traverse all accessible links from the current position and sequence the data of nearest node points. In selecting the appropriate nodes, the navigation device needs to estimate the vehicle directions and prioritize data based on the most probable directions.
A standard automotive navigation system is typically equipped with a routing and guidance feature that provides the user with a turn-by-turn guidance for a route generated between the current vehicle position and the input destination. To generate a route for the driver, the system checks the route link list sequentially to retrieve the necessary maneuver points. More recently, with the advance of the navigation system, a lane guidance feature is employed to assist the driver on the lane basis for streets with multiple lanes and intersections.
The lane guidance feature with a predetermined route provides the driver turn-by-turn guidance on the lane basis, and the system may recalculate the route if the driver does not stay on the lane suggested by the system. For example, if the driver notices that the lane he is traveling on is blocked due to accident, he may want to switch to other lanes to avoid the traffic and the system may recalculate the route for the lane change. Such route recalculation may be unnecessary since the destination remains the same and the system may be overwhelmed.
U.S. Pat. No. 6,944,538 to Ishibashi et al. discloses a navigation system which eases the burden of changing lanes, taking into consideration the traffic situation surrounding the vehicle. More specifically, the navigation system includes an image capturing device, i.e., a camera, for taking images in an area close to the rear of the vehicle, and the lane changing information is provided to the driver according to the images taken in vicinity surrounding the vehicle, as shown in FIG. 1. However, Ishibashi does not disclose anything related to provide a lane guidance system to avoid unnecessary route recalculation when the vehicle does not stay on the lane suggested by the lane guidance navigation system.
U.S. Pat. App. Pub. No. 2009/0222202 discloses a navigation system providing guidance regarding a travel route to a vehicle. More particularly, the navigation system provides more clear guidance when a lane is added to correspond to a road which is taken after a course change, as illustrated in FIG. 2. However, like Ishibashi, it does not disclose anything related to provide a lane guidance system to avoid unnecessary route recalculation when the vehicle does not stay on the lane suggested by the lane guidance navigation system.
U.S. Pat. App. Pub. No. 2007/0124072 discloses a navigation system providing lane guidance to lead the vehicle to the recommended lane. More specifically, the system receives information regarding the vehicle's current position and moving direction to determine whether the vehicle is moving toward the recommended lane. If the vehicle is moving toward the recommended lane, the system provides lane guidance to the vehicle, as shown in FIG. 3. However, it does not disclose anything related to provide a lane guidance system to avoid unnecessary route recalculation when the vehicle does not stay on the lane suggested by the lane guidance navigation system.
Therefore, there remains a need for a new and improved apparatus and method to provide guidance information to the driver without repeatedly performing unnecessary route recalculation when the driver makes slight deviation from the route without changing the destination.